Many of us wish we could afford those fancy Digital SLR's but the reality is most of us cant, or are unwilling to drop that cash on that expense atm when they could buy a bigger tank 
So for us with the crap camera's perhaps lets share what has worked for us because personally i have had decent shots and complete crap from the same point and shoot digital
First thing, you are taking a picture of a fish tank, its pretty bright, so you'll want to change the setting EV (or Exposure compensation). Somewhere between -1 and -2. Personally i've had the best results at -2.
ISO setting, more often than not auto will shoot between 200-400, which will give you decent clarity, but i noticed with many point and shoots, if you select 800, it'll show as very grainy. 800iso is meant to capture the faster moving fish so they wont seem like a streak. I've had better luck with the room lights on at iso 800. With 400 and lower, it seems to come out better when the lights in the room are off.
NO FLASH! Unless you rig an external flash above your aquarium to shine into the water, you'll get reflection. Chances are if you can do that you have an SLR already and dont need to be reading this.
Macro: Use it for close shots, sometimes it works well at a distance, but it depends on a number of factors. Sometimes i take two shots of most thigns, in macro and non macro and what comes out and what doesn't is really a flip of the coin.
White balance: Leave at auto, i know we have flourescent, and most camera's have this option, but let the camera figure it out.
Metering mode: if you are doing a close up, try spot, otherwise stick with multi
Colour: Normal
Quality: Standard works fine for the web
leave sharpness alone.
Which dial setting should i use? well each camera is different. I use a sony and prefer Program Auto mode (P on the dial) because i can switch between iso 800 and auto. If you are not after the action shots, Auto mode (green camera icon on sony's) will do fine. In most cases you'll just need to adject EV to -2 in either mode.
Remember one key thing though, every camera is different, if something works for you, remember it. Some point and shoots can give SLR like shots almost every single picture, no point venturing outside auto mode unless you need to. But i notice with planted tanks, the bright greens often throw the auto functions off a tiny bit with the lesser quality models
So for us with the crap camera's perhaps lets share what has worked for us because personally i have had decent shots and complete crap from the same point and shoot digital
First thing, you are taking a picture of a fish tank, its pretty bright, so you'll want to change the setting EV (or Exposure compensation). Somewhere between -1 and -2. Personally i've had the best results at -2.
ISO setting, more often than not auto will shoot between 200-400, which will give you decent clarity, but i noticed with many point and shoots, if you select 800, it'll show as very grainy. 800iso is meant to capture the faster moving fish so they wont seem like a streak. I've had better luck with the room lights on at iso 800. With 400 and lower, it seems to come out better when the lights in the room are off.
NO FLASH! Unless you rig an external flash above your aquarium to shine into the water, you'll get reflection. Chances are if you can do that you have an SLR already and dont need to be reading this.
Macro: Use it for close shots, sometimes it works well at a distance, but it depends on a number of factors. Sometimes i take two shots of most thigns, in macro and non macro and what comes out and what doesn't is really a flip of the coin.
White balance: Leave at auto, i know we have flourescent, and most camera's have this option, but let the camera figure it out.
Metering mode: if you are doing a close up, try spot, otherwise stick with multi
Colour: Normal
Quality: Standard works fine for the web
leave sharpness alone.
Which dial setting should i use? well each camera is different. I use a sony and prefer Program Auto mode (P on the dial) because i can switch between iso 800 and auto. If you are not after the action shots, Auto mode (green camera icon on sony's) will do fine. In most cases you'll just need to adject EV to -2 in either mode.
Remember one key thing though, every camera is different, if something works for you, remember it. Some point and shoots can give SLR like shots almost every single picture, no point venturing outside auto mode unless you need to. But i notice with planted tanks, the bright greens often throw the auto functions off a tiny bit with the lesser quality models